Self-contained variable pitch propeller unit



March 2, 194s. A, G, FORSYTH 437,188

SELF-CONTAINED VARIABLE vPITCII PROELLER UNIT Henna/uo GRAW/yn oms ww,

March 2, 1948. A. G. FoRsYTH 2,437,188

SELF-CONTAINED VARIABLE FITCH lPROPI'LLER UNIT Filed Jan. 19, 1945 'z sheets-sheet 2 www \ 'March 2, 1.948. A. G. FoRsYTH SELF-CONTAIND VARIABLE FITCH PROPELLER UNIT '7 Sheets-fSheet 3 Filed Jan. 19, 194s d-WIT k March 2, 1948. A. G. FoRsYTH 2,437,183

I SELF-CONTAINED-VARIABLE FITCH PROPELLER UNIT Filed dan. 19', 1943 7 sheets-sheet 4 Jax/gc 14106 my Rm March 2, 1948. `A. G. FoRsYTH l 2,437,188'

SELF-CONTAINED VARIABLE FITCH PROPELLER UNIT Filed Jan. 19, 1945 7 sheets-sheet 5 Sum/waag March 2, 1948. y A. G. FORSYTA 437,188

SELF-CONTAINED VARIABLE FITCH PROPELLER UNIT Filed Jan. 19, 1945 '7 Sheets-Sheet 6 Y Howe/740 @Aw/MM /ms V771,

.March 2, 1948. A. G. FORSYTH 2,437,188 l' SELF-CONTAINED VARIABLE FITCH PROPELLER UNIT Filed Jan. 19, 1943 7 Shets-Sheet '7 FEA 7HER/NG @ttm/MM Patented Mar. 2, V1948 lUNITED STATES PATENTFI'CEf SELF-CONTAmm VARIABLE FITCH 'f PROPELLER 'n Archibald Graham Forsyth,` Cheam, England-assignor to The Fairey Aviation Company Lim- Y. itedHayes, Middlesex, England p Application January 19, 1943, Serial N o. 472,882

4 claims.- (cl. 17o-16s) n' This invention relates to kvariablepitch propeller systems and more particularly to a selfcontained unit for variable pitch propeller systems. l In my copending application, Serial No. 449,123, led June 30, 1942, I have illustrated "and described a variable pitch propeller system having many advantages. The present invention from an operational standpoint lpossesses many features in common with that disclosed in the application to which reference has been made. -However, the present invention comprises a Vselfcontained unit which, as such, can be readily attached to any standard aircraft-internal combustion engine of any power'output. The unit is small in' its dimensions, light in weight and comparatively simple to manufacture, tol operate, adjust, assemble, take ydown and repair. The invention is so designed that upon mere assembly over the propeller drive shaft and simple attachment to the front facing of` the engine, the device is `ready for operation. Y,

The device comprising the invention is a complete unit with its electric motor'for changing the pitch, the. governor, switches, solenoids and de-icing pump. The onlyfconnections necessary after installationy on the propeller drive shaft being the electricalconnections to the battery, the connection of the governor range control to the cockpit or cabin, and the pipes to the deicing pump, if this be used. A

It is the principal object of the invention to provide such va device. Another important feature of the invention resides'in the particular disposition andV arrangements of the parts, a feature presenting diiiculties of attainment because of the severe requirements and space limitations. Units have been known heretofore but these have been complicated in structure, whereas the present invention eliminates complicated mechanism and results in a device which can be produced cheaply and leasily maintained While admirably fulfllling all requirements of a modern propeller control arrangement. i

Still another Vobject of the invention resides in a Vself-contained variable pitch changing control unlt adaptable for use with contra-rotating propellers mounted on co-axial drive shafts.

A further lobject of the invention resides in a unit for eiecting a change of pitch of the propeller blades and for controlling the extent of change to. suit .various operating conditions, such unit being electrically or hydraulically driven by .means carried by and comprising a part of. the unit. Y Y i .i

The invention has for a further object the provision ofy a unit .foravariable pitch propellers, which unitcan be completely 'tested before shipment. This is .made-possible by virtue of the` fact that the unit `does-.not depend onA any auxiliary connections to, or driven'- byr,an internal combustion engine. TheA present vinvention carries its own anti-freeze lubrication. Y, 'y' The device which will be described is particularly adapted for four Aengines in lparticular now in large scale productiongand in which no provision hasbeen made-Qn' the.l engine to drive a governor, pumps, or for oilducts'or the like which are ordinarily: required' for. the. usual variable pitch propeller systems. Y, 1 p i It is highly advantageous to provide .aY structure .in which the .propeller hub` structure and propellers may be removed quickly for inspection. The invention ,provides for .this in such manner as not to make necessary, the removal or disturb-l ing of the control unit, mounted-betweenthe propellerhub structure; and theengine.

These and .other objects yof the invention will be more apparent-from the Afollowing description and claims when read in the light ofthe accompanying drawings in which: i y y y Fig. 1 is a side elevation of the invention. v f

Fig. 2 is a vertical section-through thedevice shown in Figi.' f: s .r a

Fig. 3 is a front1.elevatio11..` E

, Fig. 4 is a cross sectional view taken on the line 4-44ofFig. 1. p .l

Fig. 5 is a crossA-sectionalzview showing the means for driving the governor and the cie-icing pump. Si Figs. 6 and' are sectional detailsshowing alternate-forms of.A gearing.,v l i Y Y YFig. .8y vis a partial ,view of the hub, va portion being brokenaway to show the gearing for effecting aL change in pitch of the propeller blades.

Fia29-1S a AS.ectoiial View, taken@ 011 the line 9 9 0f Fig. `8. l V i w l Y Fig. 10 isa partialsectiongoi thecam operated switch mechanism, and 1 l y;

Fig. 11 is a diagrammatic showing of thecontrol circuit. e

The self-conta-.ir-ied,` easily assembled, electrically controlled vunit comprisingthe inventionis adapted, as shown in Figs.' 1 and 2, to bemounted at the forwardfend oftheinternalcoznbustion engine 2 VVabout the-propeller d rive Ishaft v4. The unit isV adapted-to be-fitteditov the engine 2 without making any modifications in the engine. n

. Engines of the typeusedin-,airraft are usually provided with a front. facing Shaving apluralityl gear 6.6 munies@ r..

to the propeller drive shaft 4 against the engine.

thrust bearing nut which revolvesvvith the pro,.- peller shaft. Forwardly of the ring member. IB, on the propeller drive shaft is a wedge-shaped cone or collet I8, a hub sleeven 28 keyed.v to the. drive shaft 4, a second wedge-shaped colletV 22 having an inwardly directed lock ilange 24'; en-v gaged by an annular groove,2&initheloclnngnut 28 adapted to be screwed on the threaded outer l changing` mechanism. described. 1d

end of the propeller driye shaft 4. Thlocking l nut 28 is provided with openings to receive the locking pins38= which` af-terbeingpushed radially outward are secured in such. position by. wiring alas` will be clearly .apparent from. Figs. 2V and 3, The hub sleeve 28 rigidlynsupports the.. tubular member. 32.y which, at each end. threadedly. re." ceives the. sleeves. 3.4.4 Thesesleeves, in turn, receive the socketniembersA 36 in which the rootsof. the propeller blades 31s are rigidlymounted. The socket members. 861 are. threaded at their inner ends and annular worm. gears 38. are. mounted thereon and securedrigidlybylock pins, 451;, 15etween the annular worin gears and the. sleeves 34; are rollerbearings '421 f The tubular member 32 haittwo.longitudinal--l ly disposed smaller` tubular.. members M rigid therewith (see Fig.. .9). in which are. mounted worms 45- engaging the annularworm gears. 38 as will be apparent Afrom Figs. 8 and 9. Thisk structure-per se has been-"disclosed in. my co,- pen'ding application Serial No. 464,369, filed. No.

vemberS, v194:2-, vnow abandoned, towhich ref.

erence is made. The worms 48 are mounted. on.

shafts -48, the rear ends of- Whichprot-rude from the tubular mein-bers andrigidly support the spur gears 50. i The spur gears 8 are engaged lleva llarge ring gear .52' (see Fig. 1\) adapted to be driven by mechanism to be'described presentlya It should now be apparent that upon rotationfof the large ring gear 52, the spur Yg'earsf. 5Ilwill be rotated, thus actuating the wormT 485, engagingthe. annular worm gears 38. The propellerbladefsocket members se are' thus retetedabqut. their longitudinalfaxs tc'ieitec't` a change. i-nthe pitch` of: the propeller blades 3l.

W'- reference--now'to Figsz Sande, it willbe observed that the gear 52is mountedffor rotation on the mem-ber l5.' Atits inner end the. gear 52 is 'provifdek'iwithgear tethf 54 engaged by a pair of'pinins 5 8 mounted brrthe` spider 58;l

The spiderv also carries'another pair ofA pinions 60 engaging teethl 62 on the intermediate portion ofmember IGva-iid-also teeth on` a ring member 65 rigid with the housing VI-I-. T- he first` pair of pinions 58- alsoegase teeth on the ring tation on the. ringmem# han) Ring gear 5,8 has outer peripheral gear teethV engaged at one pointV b yi-"the worm 58" mounted 'n'the shait` TU (Eig. '4 andi adapted to` be rotated by the electric"'motorv 1-2-throug-h gearing T4', I6 and 18, the gearwbeing secured on the shaft 1u. -Since the member;

If6--rotates=with thepropeller drive shaft lI- at Y ll timesv the internal ombus-` ation of the electric motor 'I2 since tion engine is running, the spider 58 will rotate with the propeller drive shaftv at all times in the same direction but at a slower speed. If it is desired to change the pitch of the propeller blades, the electric motor 'I2 is energized to rotate in one direction or the other and the worm 68 will rotaterir-ig gear. 66j, thus causing rotationA of pinions 'andthr'ough them, the ring-gear 52. Obviously, ring gear 52 will not be rotated without actupinions 56, when the. motor. 12 is still, merely ride between the; ring gears 66 and 52 without driving either.

' ontrol means are provided for the pitch Such control meansperate similarly to those described and shown in my copending application, Serial No. 44Q l.25 referred to above. They are comprised of the circuit diagrammatically illustrated in Fig. ll, including the cams 8 0, 82 and 84 adapted respectively to actuate the switches 36, 88 and 90. Also included. in., the circuit are. the. control switches.Y 92;, 8,42'. actuated by the. governor. 8i drlvenbv the internal combustion. engine. The. hand switches 98, |00 provide manual control; as will be. described. hereinafter.r Also included in the circuit` is. the battery L02, the solenoids L04-, I l and. the eIectricmQtQr 1,2..

Whlenot shown in Eig. 1-1, theelectric. motor. 12;, asidefrom dri-ving; thaworm lill,v also drives the control: cams. 805, 82sA and 84, each in thedi, rection ofrthe arrowed. linesinrig. 11:. 'Ilhe.,man. ner in. whichA these controlcams mayr` berotated by. the. electric.y motor. 152 is shown in- Figs.. 2 and 4. Ring. gear. lilisen-gaged; by, a spur. gear ma havin-g a laterally extending portionA provided with aworm4 lamensegnga worm. gear blz fixed to shaft I L41 0n. whlchtlle, control.. cams. 88., 8.2VL and tillL are. mounted to. rotate. with. the shaft.

As illustrated irl-Fig. 10, the. cams, such as 80, may. beA adapted; to. engage switchA members, suchc as LIB; capable. of; reciprocating longitudinal. movement and normally urged by springv means; (notA shown), againstthe.. camL surfaces. The switch. members. Uily actuate the switches. 86, 88, and: 911;. dasrammatically shoWnin-Fig. 1l.

The governor. 9.81advantageously,may:bedriven` from. the. propeller` drive.v shaft V4; As described heretofore. .ring member Llr.- iskeyed; to-.the pr.o.A pellerdriye shaft.. Tibia-member IB. is provided with worm teeth II..8 engaging.` worm: gear. |201 carried by the shaftflf22i Gsee. Fig. 5)., one `end ofl whichisfconnected-to .drvethe governor, The otherend of. shaft lzzmaybeconnectedftoldriva other. mechanism. such. as al deeicing pump |24.- Where .a deficing pump i-s.;l1jiven by shaftl |22; it. is best to. have thel de-icing iluid piped from! a. separatecontainer (notrshownrl. Then, should? bychance thesepipesbreak, the running ofy thef propeller willv not. bel ailected in any-way.

Alternative arrangementsfor' driving the governorare illustrated-lin Figs. Sand '1. In each of.A thesegures the member IB-doesnot have-Wormu teeth. Ila as insFig. 2; but-in lieu thereof `(Fig.v 6i)a the spider 58 itself carries a hanged.: annular ring- |26V provided withY teeth I-28- for engaging worm |20; The. arrangementiin- Fig. '1: has a similarri-ng |38, carried-fby.A the spider-i533, said ring Illf being org-reater diameter. than. ring1 I 28 and hav, ing4 teeth. I e2 .l on. its. outerperiphery, With such arrangements, different operating. ratios can be. attainedA It is. effaceur-se apparent thatuseoti such. arrangementsrequiresa. relocation..4 offshaft. I2-2 and 'worm` I.2 Mfurther totheleft of-,theposi' tion in. which thema-re.. shown irl-Eig.` 5l 'Iiiesev alternate arrangements for driving the governor-. 1

are- 'sometimes necessary.1For example, if the propeller shaft i's driven directly by the internal combustion engine without lthe use of'intermediate reduction'gearing, the governor would operate much toofast for. practical use.; The alternate arrangements shown make it possible to reduce the governor speed very simply, thus rendering the unit even moreadaptable to all types of. engines whether or not they be provi-ded with reduction gearing.

It is believed 'expedient at this point to describe generally the operation of the invention. From the legends on Fig, '11, it Will be seenthat switch 98 Vis, a hand-feathering switch. Switch 00 isv also a hand-operated switch for overriding. theV governor 98,-at the will ofthe pilot. Switches 88,.

88 and 90 are respectively, fine pitch, coarse pitch and-feathering pitch limit switches. If .desired a. fourth switch. and cam` (not shown) may be employed for'reverse pitch. AA' circuit adapted forthis purpose isV shown in my copending `application SerialNo.449,123.

. lThe, finel pitch limit switch 88 and the coarse pitch limit switch 88 are vbothlocated in then-or-v mal circuit ,and are so arranged as to remain 6, when the-engine is running; With such an arrangement, when the aircraft is about to land' with 'the engine throttled, the blades are brought toy ne pitch position.' and! when on the ground after the engine is'stopped, the blades will continue to move toward line pitch until the electric motor is stopped by the fine vpitch limit switch 88. This insures that the blades are always left ina nepitch position for a take-off.

Should it become necessary for any reason to override the governor, this may be accomplished by the pilot by manually operating the hand controlled switch |00, which isin the circuit indicated'iby dot and dash lines. Thus, in accordance with .the actuation of this switch and the consequent cutting out of the governor, the electric motor 12 can be actuated either in the direction of coarse pitch and it ls then only shut off by the actuation of the hand controlled switch |00l or by actuationof the fine pitch and coarse pitch limit` switches 88 Vor 88. v

,When it. is desired to feather the propeller blades, it is necessary for thepilot to actuate i the hand featlieringv switch 98 so that the norclosed during normal operation. Hand feathering switch98 is normally in the position shown in Fig. 11 so that the feathering circuit (shown in broken lines) is normally broken.

The governor, driven by the internal icombuks;

tion engine, as described, is iirst adjusted by actuation of the hand lever 95, not shown, connected for operation from the cockpit. The adjustment of the governor forms no feature of the present invention. It is shown and describedin myV copending application Serial No. 449,123 to which reference may be had. The governor actuates the pivoted switch lever 91 so that ituwill either close the ne pitch switch 92 or the coarse pitch switch 94. In accordance with which of these switches is actuated, the electric motor '|72Y will rotate in one. direction or the other towardne pitch or coarse pitch. Oper` ation of the electric motor, asv described, rotates the cam members80, 82 and 84 and if the electric motor 'I2 rotates for too great a length of time in either of the two directions, the `cam members 80 andy 8,2 will' actuate either the iine pitch limit switch 88 or nthe coarse'pitch limit switch 88, thus breaking fthe normal circuit and cutting off 'the electric motor. l

y The fine pitch limitswitch 88 and the coarse which is, by meansA pitch 'limit switch 88 control the predetermined coarse and nepitch ypositions of the propeller blade'p't'ch."4 For examplefthe fine pitch Ilimit switch' 86 only comes into operation during takeoff and the Icoarse pitch limitswitch 88 acts to prevent overpitching ina dive. As will be described later, this switch is closed by the feathering control switch 98 thereby attaining thefeathe ering ,position to be determined by cam 84. In

normal flight `the pitchof the propeller blade will remain substantially .constant intermediate between iine and coarse pitchand the cams 80 and 82 are so arranged that they will not break the normal circuit unless the predetermined dangerous limits of fine andfcoarse tained.

The governor arrangement illustrated in Figure 11 is similar to that shown in Figs. 2 and 3 of my application, Serial No. 449,123. It will be noted from that application that when the engine is stopped, the spring on the governor moves the weights into line pitch position, closing the switch 82. The coarse pitch switch 84 can only be closed JDitch are atj the feathering circuit, passes current through ther contacts of the feathering limit switch and at the same time, since the coarse pitch limit switch 88 is bridged and dead, the cam 82, though tripping thev coarse pitch. limit switch 88, will noty shut-oli the electric motor 12. The feathering cam 84 is so designed that if the pitch change inthe-.direction of Vfeathering becomes excessive, thiscamwill trip thev feathering limit switch 90 and thus shut-oir the electric motor. When'the feathering limit switch 90 is broken, the fine pitch limit switch.86 is still alive, and because of.

the fact that the governor has moved the pivoted switch lever91 into ne pitchposition, the elec.

tric motor A.l2 isireversed and` consequently the pitchlor the propeller is restored to normal running position somewhere between the limits deiined by the yfine pitch limit switch 88 and the coarse pitch limit switch 88.

It should also4 be obvious that actuation of the hand controlled switch |00 can be used to bring the propeller blades back to normal position. It is necessary, of course, to return the feathering switch 88 to the position shown in Figure 11 so asto breakvthe feathering circuit and close the normal running circuit. 'g

l Attention vis calledt the .fact that with the hand controlled switch |00, it is not only possible to override the governor but to change the f pitch of the propellers at will and to leave the blades set J at the best position for economical cruising. For example, the blades can be feathered by operation of this switch |00 provided that the 'feathering switch 98V is put into feathering position.YK switch |00 ina counter-clockwise direction from the position shown, the YVlrst set of terminals will cut out the governor and complete the ne pitch circuit. Moving it clockwise to the rst set of terminals in that direction will close the coarse pitch circuit. Continuing in the same direction, to a position at right angles to the iirst position, will effect an ofi position in which the blades As shown in Figure 11, moving the are locked. 'Ihls switcn mit ahviousla" can; be rotated, as much. as; 3,609-imeithelt. direetiiin@` will be. apparentthatusnaiiys thefs vriiiislaf11.Il!:willy remain in. a normal runnne position; in which the governor isin actuation. but canine used.. for example, on long-2 cruises. and; the. like. so. that-.the pilot can: set` the pitch.. in. thel best: possibiefsposifa tion for. economical operation.V

While, in general; the structure fors accom:` plishing the desired' resultshas; been` described, it should be pointed. ontV that. one. ofthe principal objects. of the invention` residesdm theparticlb- .lar form andl disposition off' the: venous. parts'.

With but very little workingA space` available', the( invention admirably utilizes this` space; to the best advantage` while at::the same time; the. inf-f vention is comprised-ofselfwontainedunits which. are readily. assembled: and removed;

In applying the unit, it is.r only; necessaryv` to attach member Inzto the engine. facing.YV 6; hm nuts I2, slide member I6 om the: propeller. drive shaft add the housing- Mi vizitlr` mechanism therein and the mechanism carried thereby; togetherwith ring gear 52 inpiaoeoni` member l5; and then complete thestructure by.: adding: cone or collet i8; propeller. hub. sleeve 20'. andfthe' hub. structure proper is.- d'escribeda hereinbeforevr the collet 22', the locking, nut 28 andlockinepins 311'. Itis manifest that the4 unit-may.- be; taken down or dismantledwith equalfacllity.

It will also be apparent thattheunitirequiresf.. nov conduit connections; to: the. interinali combustion engine and. further that; being.: driven. by: electricalV means, no 1 useV off congeaiable cri-1;'` fromtheengine isf required.

It will be. noted' furtherfthattheihousingi Mzoil the unit isv adapted to=V contain its-own lubricatetion, which preferably. mavbe of f the anti-freezeY variety?.

While it has not been herein, itffwill' be apparent that the. invention manv bey employedi with two hublstruoturesmountedonA coaxialpro-.-l pellerv drive shafts.. Iny such instance, the pitch-f. changing gearing for the. orwardihuo-structurei maybe similar to thatshownherein; andsmayj be driven by a. gear onv the-otherlendioffshafti. ('see Fig. 9) byv connect-ing;gearineysuclr asrthatf shown in Fig. 5.` of.l my..sa,pplication.Serla1e No, 465,618', leol November 14.; IMZLnOvofPfatentNo.. 2,426,007, for inzFig; 9'of.'myaapplicatiornSeriaINo,v 449,123.

Changesin structuxemay:bervmadeewthout departing from the concept ottheeinventiaon-whichi should notl be limited, iny seopeexeeptifto-.that en.4 tent indicatedin the. f-ollowingclaims.'

I claim:` i v l. A control un-itlfonvariabla; pitch-.proponen systems having propeller huh.stiuotnre'-.provided3 with pitch changing gearing;` saidunittheingfdimensioned to beremovably.: sitionedasurround-e; so, Number.

ing. the propeller drive-shaftbetween the-*proa peller hub structure andtheeneipew-ith the pro.;-r peller drive shaft.` extendingentirehnthmugnthe. unit, said control uniteomprisins af sleeye. tendina substantially; the.` entice-i axialtlensth. on the. unit and comprising; the; annulaiarini1erewallsv or; the... unit; .means mounting naief-sleeve. infames.- sition surronndnefthfn proponen-drive shainior;

l pinions4 carried; by.: said; spider;` one; pair; of said pinions; engaging; the, teeth. on saidtf sleeve and theteetnonlsaidrineggear; asecond` toothed ring gear: mountedfor rotation about said. sleeve, a, thirdtnothed' ring mounted forrotationon; a porlit tion of said sleeve, a second pair ot saidpinons engaging'said. second toothed` ring gear and said third-toothed ring, motor means for. driving said second'. toothed ring gear, said third toothed'lring having a gear portion eneageabie with the pitchm changing gearing. of the propeller hub structure,

and a.. housing, said housing supportingsaid; motormeans; said' housingy and said' sleeve together comprising: acomplete: enclosure for alli of: the.` other nam-edt. elements off said unit with g@ the exception of said gear portion and' sai'dmotor' means, and'` providing unitary support for the entire unit.

2.- A- controlunit as set forth in claim 11a governor-carr-ied by thek housing, a drive shaft with-` 25 in-thehousing and driven by-said sleeve'foridriving the governor, andA switch means. actuated by; the governorfor controlling said motor.

3i A cont-rol unit as set forth in` claim 2`, cam means within said housing and operated by'saidy 3o second toothed ring gear, and switch meanscarried by said housing4 and opera-bleby said cam meansl for overriding said governor.

4. Al control unit as set forth in claim 1', a. governor'carried' by the housing; adriveshaft'withthehousing fory driving said governor; aring gear carried bysaid' spider for driving` saiddrlve.;

shaft, and switch means actuated by the' governor tor-controlling the motor.

ARCHIBALD GRAHAM FORSYTH;

REFERENCES CITED .l

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